RA CAPITAL MANAGEMENT, L.P. bought ABOS

Footnotes

Represents a restricted stock unit ("RSU") award to Laura Stoppel. Each RSU represents a contingent right to receive one share of the Issuer's Common Stock. The RSUs will vest in full on the earlier of the first anniversary of the date of grant or the 2027 annual stockholder meeting, subject to Dr. Stoppel's continuous service through such vesting date.; RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"), RA Capital Nexus Fund II, L.P. (the "Nexus Fund II") and a separately managed account (the "Account"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, the Fund, the Nexus Fund II, Dr. Kolchinsky, and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.; Under Dr. Stoppel's arrangement with the Adviser, Dr. Stoppel holds the RSUs and the option for the benefit of the Fund, the Nexus Fund II and the Account. Dr. Stoppel is obligated to turn over to the Adviser any net cash or stock received upon exercise of the option or settlement of the RSUs, as applicable, which will offset advisory fees owed by the Fund, the Nexus Fund II and the Account to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the RSUs, the option and the underlying common stock.